Controllable emitter

ABSTRACT

A controllable emitter of an irrigation apparatus including a drip line having pressurized fluid therein is provided. The controllable emitter includes a container coupled to the drip line, the container being formed to define an interior and including an inlet through which the pressurized fluid is receivable in the interior from the drip line and an outlet through which the pressurized fluid is exhaustible from the interior, a magnetic stopper, which is normally disposable in a first position such that the magnetic stopper prevents a flow of the pressurized fluid through the outlet and which is actively disposable in a second position such that the magnetic stopper permits the flow and a controllable actuator configured to generate a magnetic field operable to urge the magnetic stopper to move from the first position to the second position.

BACKGROUND

The present invention relates to a controllable emitter and, morespecifically, to a controllable drip line emitter using a solenoid coiland a magnetic stopper.

Current drip irrigation systems are often equipped with pressurecompensated emitters that can deliver a certain amount of water tonearby areas based on the fabrication characteristics of the emitters.Typically, the emitters will have a watering rate of 0.5, 1 or 2 gallonsper hour delivery. The amount is set in the fabrication process or theycan be set manually in the field. This can present problems, however,because industry frequently demands that drip irrigation systems be ableto dynamically adjust the amount of water that is delivered to aspecific location based on real time information (satellite imagery,field deployed soil moisture sensor, thermal imagery) of the waterabsorbed/transpired by canopy and water evaporation from soil or soilwater retention properties.

Current approaches to the problem of using emitters with a predefinedwatering rate in a drip irrigation system in which dynamic adjustmentsare required rely on delivery of the same amount of water in everylocation where the amount of water is defined as the upper amountrequired by the most water demanding spot. The inherent differences insoil properties and crop characteristics can thus lead to overwateringin many locations based on such uniform water delivery. Potentially,different rate emitters can be installed in different locations buttemporal changes in the irrigation schedule does not permit dynamicadjustments over time.

SUMMARY

According to one embodiment of the present invention, a controllableemitter of an irrigation apparatus including a drip line havingpressurized fluid therein is provided. The controllable emitter includesa container coupled to the drip line, the container being formed todefine an interior and including an inlet through which the pressurizedfluid is receivable in the interior from the drip line and an outletthrough which the pressurized fluid is exhaustible from the interior, amagnetic stopper, which is normally disposable in a first position suchthat the magnetic stopper prevents a flow of the pressurized fluidthrough the outlet and which is actively disposable in a second positionsuch that the magnetic stopper permits the flow and a controllableactuator configured to generate a magnetic field operable to urge themagnetic stopper to move from the first position to the second position.

According to another embodiment, a controllable emitter of an irrigationapparatus including a drip line and a control station configured tocontrol a pressure of pressurized fluid in the drip line is provided.The controllable emitter is disposable along the drip line and includesa container coupled to the drip line, the container being formed todefine an interior and including an inlet through which the pressurizedfluid is receivable in the interior from the drip line and an outletthrough which the pressurized fluid is exhaustible from the interior, apiston, including a magnetic element, disposed at least partially in thesecond container to occupy a position in accordance with the pressure ofthe pressurized fluid and a sensor configured to sense a position of themagnetic element and to communicate a sensed position to the controlstation.

According to yet another embodiment, an irrigation apparatus is providedand includes a drip line having pressurized fluid therein, a controlstation configured to control a pressure of the pressurized fluid and acontrollable emitter disposed along the drip line. The controllableemitter includes a container coupled to the drip line, the containerbeing formed to define an interior and including an inlet through whichthe pressurized fluid is receivable in the interior from the drip lineand an outlet through which the pressurized fluid is exhaustible fromthe interior, a piston, including a magnetic element, disposed at leastpartially in the second container to occupy a position in accordancewith the pressure of the pressurized fluid and a sensor configured tosense a position of the magnetic element and to communicate a sensedposition to the control station.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention. For a better understanding of the invention with theadvantages and the features, refer to the description and to thedrawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The forgoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of a drip irrigation system;

FIG. 2A is a side view of a controllable emitter with a solenoid coiland a magnetic stopper in accordance with embodiments;

FIG. 2B is a side view of a controllable emitter with a solenoid coiland a magnetic stopper in accordance with embodiments;

FIG. 3 is a perspective view of a magnetic stopper in accordance withalternative embodiments; and

FIG. 4 is a schematic illustration of a magnetic stopper in accordancewith further alternative embodiments;

FIG. 5 is a side view of a controllable emitter with a solenoid coil anda magnetic stopper in accordance with alternative embodiments;

FIG. 6 is a side schematic view of an irrigation system in accordancewith alternative embodiments;

FIG. 7 is an enlarged side view of a T-junction of the irrigation systemof FIG. 6;

FIG. 8A is a side schematic view of an irrigation system in accordancewith further alternative embodiments;

FIG. 8B is a top down view of an irrigation system;

FIG. 9A is a schematic view of an irrigation system in accordance withalternative embodiments; and

FIG. 9B is a schematic view of a hierarchy of irrigation system controlin accordance with embodiments.

DETAILED DESCRIPTION

A controllable emitter is provided. The controllable emitter can bedeployed in, for example, a drip irrigation system and allows a variableof amount of water to be delivered to a specific location of the dripirrigation system over a period of time. The controllable emitterincludes a solenoid coil slid over a tubular element that drips thewater. The upper part of the tubular element is normally blocked by amagnetic stopper in the shape of a sphere or a cone. When a current isapplied to the solenoid coil, the solenoid coil creates a magnetic fieldthat forces the magnetic stopper to move out of the blocking positionand thereby allows water to flow through the tube. The current appliedto the solenoid coil can be direct current (DC), such that the magneticstopper may be displaced continuously, or alternating current (AC), suchthat the magnetic stopper may be displaced periodically. The solenoidcoil may be electrically coupled to an electronic circuit that containsa microcontroller that can receive a command from an external device anda memory unit on which schedule and timing information of the magneticstopper movement is stored. Each controllable emitter of a given dripirrigation system can be addressed individually and a specific schedulecan be uploaded wirelessly or over a wireless network into the memoryunit such that each emitter can have an independent schedule. By keepingthe magnetic stopper in a position where water can flow through thetubular element and timing the period it allows the water to flowcombined with a feedback mechanism that measures water flow, the amountof delivered water can be determined by the microcontroller. The systemwill thus deliver variable amounts of water to any location subject tothe drip irrigation system by uploading an individual watering schedule.

A system and method for applying variable amounts of water or fertilizerover a region, such as agricultural land, using a drip irrigation systemis also provided. The system and method include installation of dripirrigation lines along a diverter line such that the water used forirrigation is allowed or restricted to pass through the lateral dripirrigation line using a T-junction. The T-junction has a solenoid valveand a check valve. The lateral drip irrigation lines can be assembled invariable length segments and the filling of the drip irrigation lineswith water can be controlled using the T-junction and the diverter line.By controlling the solenoid valves, an amount of fluid, fertilizer orchemicals delivered to an associated area can be controlled by adjustingthe time the solenoid valves are open and knowing the number ofcorresponding emitters and their respective emission rates.

In addition, an automated method of controlling valves to apply variableamounts of water or fertilizer over an extended agricultural land isprovided and uses a minimized modification to an existing driplinesystem. The method takes advantage of the concept that the same amountof water from a central line can be delivered either by usingemitters/nozzles that have higher emission rates (gallons per hour) andrequiring less watering time or extending the watering time ofemitter/nozzles that have lower emission rates. The approach proposes toinstall on/off solenoid valves along a dripline to control water flowand using emitters that have different emission rates along the line.The higher emission rate emitters/nozzles are positioned farther fromthe main water distribution line while smaller emission rateemitters/nozzles will be closer to the main water distribution line. Theemitters are inserted such that their emission rate increases from lowto high along the line with the low emission rate emitters beingpositioned closer to the main water distribution line. Thus, bycontrolling the solenoid valve open/closed position for differentperiods of time, the amount of water delivered to a specific locationcan be increased or decreased.

In all embodiments described above, power can be derived from a powerline or form solar paneling. Certain aspects of the timing may beaffected and determined by the availability and costs of such power.

With reference now to FIG. 1, an exemplary drip irrigation system 10 isprovided. The drip irrigation system 10 may be deployed over arelatively large area, such as a farm or a field that requires apredefined amount of water delivery above and beyond the amount providedas atmospheric accumulation. The drip irrigation system 10 may includemultiple drip lines 11, a plurality of emitters that can be controllableemitters 12 disposed along each of the multiple drip lines 11, a fluidsource 13 and a control station 14. Each of the multiple drip lines 11is fluidly coupled to the fluid source 13 wherein the fluid source 13provides a fluid, such as water, to each of the multiple drip lines 11as a pressurized fluid.

The provision of pressurized fluid to each of the multiple drip lines 11may, in some cases, be pressure controlled while the plurality ofemitters (i.e., the controllable emitters 12) can be pressurecompensated.

The control station 14 may be embodied as a computing device 140 havinga processing unit 141, memory units 142 and an actuator unit 143. Theprocessing unit 141 may be electrically coupled via the actuator unit143 to each of the plurality of controllable emitters 12 distributedacross the field to thereby provide for effective local control commandsto the controllable emitters 12. The processing unit 141 is thusconfigured to cause each of the plurality of controllable emitters 12 tobe actuated and to allow the pressurized fluid to drip independently ofone another. The memory units 142 have instructions stored thereon,which, when executed, cause the processing unit 141 to operate inaccordance with the methods described herein.

With reference to FIGS. 2A and 2B, each of the plurality of controllableemitters 12 may include a container 20, which is fluidly coupled to thecorresponding drip line 11, a magnetic stopper 30 and a controllableactuator 40. The container 20 includes a body 21 that is formed as atubular element to define an interior 210, an inlet 22 through which thepressurized fluid is receivable in the interior 210 from thecorresponding drip line 11 and an outlet 23 through which thepressurized fluid is exhaustible from the interior 210. As shown inFIGS. 2A and 2B, the corresponding drip line 11 may be disposed in asubstantially horizontal orientation (i.e., it extends along a plane ofthe irrigated region) wherein the container 20 extends in asubstantially vertical (i.e., downward) orientation.

The magnetic stopper 30 is normally disposable in a first position (seeFIG. 2A) such that the magnetic stopper 30 prevents a flow of thepressurized fluid through the inlet 22 and the outlet 23. The magneticstopper 30 is also actively disposable in a second position (see FIG.2B) such that the magnetic stopper 30 permits the flow of thepressurized fluid through the inlet 22 and the outlet 23. That is, inthe embodiment of FIGS. 2A and 2B, the magnetic stopper 30 experiences adownward pressure due to the pressurized fluid and a gravitational forcein the substantially vertical direction. Thus, with the container 20extending substantially vertically downwardly from the correspondingdrip line 11, the magnetic stopper 30 normally sits in the inlet 22. Inthis condition, the magnetic stopper 30 has sufficient size (i.e.,diameter) to block the flow of the pressurized fluid through the inlet22 and the outlet 23. However, when the magnetic stopper 30 is urged tomove toward the second position, the magnetic stopper 30 ceases to blockthe flow of the pressurized fluid through the inlet 22 and the outlet23.

With reference to FIGS. 2A, 2B, 3 and 4, the magnetic stopper 30 may beprovided in various shapes and sizes. For example, as shown in FIGS. 2Aand 2B, the magnetic stopper 30 may be a spherical ball-shaped element31 formed of ferro-magnetic material. As another example, as shown inFIG. 3, the magnetic stopper 30 may be a conical element 32 formed offerro-magnetic materials. In each case, the container 20 may furtherinclude a porous support element 24 that is coupled to the body 21 atthe inlet 22. The porous support element 24 may be substantiallyfrusto-conical and serves to maintain a lateral position of the magneticstopper 30 when the magnetic stopper 30 is urged to move toward thesecond position so that the magnetic stopper 30 can be reliably returnedto the first position.

As yet another example, as shown in FIG. 4, the magnetic stopper 30 maybe a spherical ball-shaped element 31, which is formed to define abore-hole 310. The bore-hole 310 extends from one side of the sphericalball-shaped element 31 to the other and may be sufficiently sized to sitin the inlet 22. In this embodiment, the first position of the magneticstopper 30 is characterized in that the axis of the bore-hole 310 ismiss-aligned with respect to the axis of the container 20 and themagnetization of the material of the magnetic stopper 30 such that flowof the pressurized fluid through the inlet 22 and the outlet 23 isblocked. Due to the position and sizing of the spherical ball-shapedelement 31 with the bore-hole 310, the magnetic stopper normally assumesthe first position. The second position is characterized in that theaxis of the bore-hole 310 is aligned with respect to the axis of thecontainer 20 such that the flow through the inlet 22 and the outlet 23is permitted.

The controllable actuator 40 is configured to generate a magnetic field,which is operable to urge the magnetic stopper 30 to move from the firstposition to the second position (as in the embodiments of FIGS. 2A, 2Band 3) or to urge the magnetic stopper to rotate from the first positionto the second position (as in the embodiment of FIG. 4). The rotation iscaused by the interplay between the fluidic forces that tries to movewater through the bore-hole 310 and the electro-magnetic force thattries to align the stopper magnetization with the magnetic field createdby the solenoid coil 41. In accordance with embodiments, thecontrollable actuator 40 may include a solenoid coil 41, which is formedof a conductive element that is electrically coupled to the processingunit 141. The solenoid coil 41 is supportively coupled to the container20 and, where the body 21 of the container 20 is formed as the tubularelement, the solenoid coil 41 may be slid around the outer circumferenceof the body 21.

With this construction, the processing unit 141 of the control station14 may be configured to apply current to the solenoid coil 41. Thiscurrent generates the above-noted magnetic field, which interacts withthe magnetic stopper 30 to cause the magnetic stopper to move (orrotate) from the first position to the second position. The processingunit 141 may execute this routine in accordance with a predefinedschedule or current conditions (i.e., during a dry spell, the amount oftime the magnetic stopper 30 is urged toward the second position isincreased so as to permit a larger amount of the pressurized fluid toflow through the outlet 23). Moreover, the current applied to thesolenoid coil 41 may be provided as DC or AC. In the former case, themagnetic stopper 30 is continuously urged toward the second positionwhereas, in the latter case, the magnetic stopper 30 oscillates betweenthe first and second positions.

In accordance with alternative embodiments and, with reference to FIG.5, a controllable emitter with variable rate emitter feedback (CEVREF)50 is provided. In this case, the CEVREF 50 includes first and secondcontainers 51 and 52 disposed on opposite sides of the correspondingdrip line 11. Again, the corresponding drip line 11 may be disposedsubstantially horizontally as described above with the first and secondcontainers 51 and 52 disposed substantially vertically upwardly anddownwardly from the corresponding drip line 11, respectively. The firstand second containers 51 and 52 are each provided as tubular elements,but the first container 51 may be closed at its distal end 510 whereasthe second container 52 is open at its distal end 520. The CEVREF 50further includes a chamber 53, a spring-loaded piston 54 and a lineardisplacement sensor 55. The chamber 53 is fluidly coupled to the openend 520 of the second container 52 and has a lower surface 530 with anopening defined therein. The spring loaded piston 54 is operablydisposed in the CEVREF 50 to be movable in the substantially verticaldirection with respect to the corresponding drip line 11.

The linear displacement sensor 55 is coupled to both the first container51 and the spring-loaded piston 54 and is configured to determine avertical position of the spring-loaded piston 54. In accordance withembodiments, the linear displacement sensor 55 may include anencapsulated magnet 550, which is encapsulated in the spring-loadedpiston 54 and a magnetic field sensitive sensor, such as a giantmagneto-resistive (GMR) sensor 551.

With this construction, the CEVREF 50 is controllable in accordance withthe readings of the linear displacement sensor 55. That is, as thepressurized fluid flows through the corresponding drip line 11, thepressurized fluid will push down on the spring-loaded piston 54. Thus,the higher the flow rate of the pressurized fluid, the greater thelinear displacement of the spring-loaded piston 54 and the further theencapsulated magnet 550 will be pulled from the GMR 551. An outputsignal of the GMR 551 may be receivable by the control station 14 andwill be calibrated as a function of sensor-magnet position. A drip rateof the CEVREF 50 is thus controllable by varying the pressure of thefluid in the corresponding drip line 11.

In accordance with further embodiments, the spring-loaded piston 54 maybe formed of magnetic material and the CEVREF 50 may further include anadditional controllable actuator 56. The controllable actuator 56 may beprovided as a solenoid coil 560 that can be wrapped or slid around theouter circumference of the chamber 53. As described above, theprocessing unit 141 can apply DC or AC to the solenoid coil 56 to urgethe spring-loaded piston 54 formed of magnetic material toward the openend 520 of the second container 52 or the lower surface 530. Such effectcan either block the flow of the pressurized fluid out of the chamber 53or encourage an increased amount of the pressurized fluid to flow out ofthe chamber 53.

In accordance with further aspects of the invention and, with referenceto FIGS. 6-8A and 8B, a drip irrigation system 100 is provided. The dripirrigation system 100 includes a diverter line 101 and drip irrigationsystems that are joined together at the beginning and at the end of thedrip irrigation line. The drip irrigation system 100 further includesdrip irrigation lines 102, which are similar to the drip lines 11described above, and T-junctions 103. The drip irrigation lines 102 aredisposable substantially in parallel with the diverter line 101 and areformed to define irrigation segments along their respective longitudinallengths. The pressurized fluid contained in the diverter line 101 isprovided to the drip irrigation lines 102 and flows outwardly throughirrigation holes defined in the drip irrigation lines 102. In somecases, each of the drip irrigation lines 102 may have lengths that canbe adjusted according to spatial resolution of sensing zones.

The T-junctions 103 are each interleaved between adjacent ones of thedrip irrigation lines 102. As shown in FIG. 7, each T-junction 103includes a three-way line 110, which is coupled to the diverter line101, a check valve 120 and a controllable valve 130. The check valve 120is operably disposable between the three-way line 110 and a downstreamend of an upstream one of the drip irrigation lines 102 to permit fluidflow in only a forward direction (see the arrows in FIG. 6). As such,the check valve 120 prohibits fluid flow in the reverse directionwherein fluid can only flow through the drip irrigation lines 102 in theforward direction. The check valve 120 can include a simple mechanicalflap that is opened/closed by fluid pressure or a spring-loaded nozzlethat is actuated by the pressure of the fluid in the drip irrigationline 102. The check valve 120 may also include a solenoid valve that isselectively opened/closed in a manner similar to the controllable valve130 as discussed below. In any case, the check valve 120 is complementedby the controllable valve 130 that is selectively opened/closed asdescribed below.

The controllable valve 130 is operably disposable between the three-wayline 110 and an upstream end of a downstream one of the drip irrigationlines 102. In that position, the controllable valve 130 is operable in afirst mode and a second mode. In the first mode, the controllable valve130 permits fluid flow in only the forward direction (as illustrated bythe arrows in FIG. 6). In the second mode the controllable valve 130prevents the fluid flow in the forward direction.

In accordance with embodiments, the controllable valve 130 of each ofthe T-junctions 103 may include a solenoid valve 140 where the solenoidvalve 140 is operably coupled to, for example the control station 14described above. In these cases, the control station 14 is configured toapply a current to the solenoid valve 140 or not apply the current tothe solenoid valve 140 such that the controllable valve 130 operates inthe first mode or the second mode, respectively. The determination ofwhether to apply the current or not may be made by the control station14 based on a predefined irrigation schedule defined in accordance witha predefined temporal resolution and/or historical data or currentatmospheric conditions. In some cases, the control station 14 can issuecommands to individual controllable valves 130 to hereby control anamount of fluid delivered to an area proximate to the correspondingcontrollable valves 130.

Each of the solenoid valves 140 may be configured to acknowledge receiptof a command to open or close from the control station 14. In addition,each of the solenoid valves 140 may be configured to report back to thecontrol station 14 that a received command was performed or executed.Along with signals from sensors relating to current atmospheric and soilcondition, these reports from the solenoid valves 140 may be employed bythe control station 14 in a closed loop feedback control system.

In accordance with further embodiments and, as shown in FIGS. 8A and 8B,the drip irrigation lines 102 may be disposable on both sides of thediverter line 101 such that additional area can be covered by the dripirrigation system 100. In these embodiments, multiple ones of theT-junctions 103 may be disposable at similar axial locations along thediverter line 101 and two or more drip irrigation lines 102 may becoaxial with one another at each of those similar axial locations. Inthe particular embodiment illustrated in FIG. 8A, the irrigation holesof each of the drip irrigation lines 102 at any one axial location ofthe diverter line 101 may be oriented in opposite directions so as tospray pressurized fluid over twice the proximal area.

In any case, for any section of irrigated area associated with aparticular drip irrigation line 102, pressurized fluid will flowoutwardly through the irrigation holes only when the controllable valve130 is opened. Thus, an amount of irrigation in that section iscontrollable by adjusting the time the controllable valve 130 is openand knowing the number of emitters per segment and their respectiveemission rates. Moreover, one or more controllable valves 130 can beopened and closed at the same time such that they can have a commoncontrol cycle. In addition, the drip irrigation lines 102 may be movedacross a field and the controllable valves 130 at various sections canbe activated or deactivated (i.e., controllable valves 130 areidentified as being activated where they have an “O” and as beingdeactivated where they have an “X”, as shown in FIG. 8B) at varioustimes and for various time periods. In this way, various sections of thefield can be irrigated at various intervals and by amounts of fluid thatare appropriate for current conditions at those sections.

At the upstream and downstream ends of the drip irrigation lines 102,the drip irrigation lines are coupled to the diverter line 101 and asingle controllable (i.e., solenoid) valve may be provided at the farend of the diverter line 101 and would be normally closed. These valveswill stop water from escaping from the drip irrigation lines 102 butwill be opened when the system has to be flushed to be cleaned fromdebris and organic material. For flushing, a command is issued to all ofthe controllable valves 130 (i.e., all of the solenoid valves 140) tostay opened and water is pumped at high pressure through the dripirrigation lines 102.

With reference to FIGS. 9A and 9B, irrigation lines such as the mainirrigation lines 11 and 101 described above are commonly fitted withreplaceable nozzles or emitters (hereinafter referred to as “emitters”)that are pressure compensated and can have the same drip rates. Thetypical drip rate (hereinafter referred to as “emission rate”) would bebetween about 0.25 gph (gallons per hour) up to about 8 gph. The amountof water delivered by a system using such features can be calculated bymultiplying the emission rate with time. Thus, a 2 gph emitter that isoperated for 2 hours will emit the same amount of fluid as a 1 gphemitter that is operated for 4 hours. As such, the same amount of fluidcan be delivered by choosing a higher emission rate emitter that isoperated for a short time or by operating a lower emission rate emitterfor a longer time.

In accordance with aspects of the invention, an irrigation system 200 isprovided. The system 200 includes a main water supply line 201 and oneor more lateral driplines 202 fluidly coupled to the main water supplyline 201. Each of the one or more driplines 202 is divided into segments(or zones) 203 that are separated from one another by a controllablevalve 204, such as a pressure regulating or solenoid valve 2040. Thecontrollable valve 204 can be actuated (i.e., turned on and off) by avoltage pulse issued from control station 14 similar to the mannerdescribed above.

As shown in FIG. 9, each of the one or more driplines 202 is equippedwith a plurality of emitters 205 such that each dripline 202 has a groupof emitters 205 in each zone. Each emitter 205 is activated when thecontrollable valve 204 associated with the corresponding zone isactuated or turned on. The one or more driplines 202 are arranged suchthat groups of emitters 205 for each one of the driplines 202 may beprovided in each zone.

The one or more driplines 202 are further arranged such that higher rateemitters 205 are disposed toward the end of the corresponding dripline202, which is remote from the main water supply line 201. The loweremission rate emitters 205 are then disposed closer to the main watersupply line 201. Thus, in zone 4, the emitters 205 have a high emissionrate, in zone 3, the emitters 205 have a medium high emission rate, inzone 2, the emitters 205 have a medium low emission rate and, in zone 1,the emitters 205 have a low emission rate. As such, in order to maintaina uniform amount of fluid delivered to zones 1-4, the emitters 205 inzone 4 need to be activated for the shortest time, the emitters 205 inzone 3 need to be activated for the next shortest time, the emitters 205in zone 2 need to be activated for the next shortest time after that andthe emitters 205 in zone 1 need to be activated for the longest time.For this to occur, the controllable valves 204 (V4) between zones 3 and4 need to be opened for the shortest time, the controllable valves 204(V3) between zones 2 and 3 need to be opened for the next shortest time,the controllable valves 204 (V2) between zones 1 and 2 need to be openedfor the shortest time after that and the controllable valves 204 (V1)between the main irrigation line 201 and zone 1 need to be opened forthe longest time.

In some cases, it is to be understood that it will not be necessary ordesirable to provide a uniform amount of fluid to each of the zones 1-4.In such cases, time multiplexing may be employed to vary an amount offluid delivered to some of the zones but not others (i.e., to provide arelatively large amount of fluid to a central area and relatively smallamounts of fluid to outer areas). For example, if the controllablevalves 204 in zones 1-4 have respective emission rates of 0.5, 1, 2, 4gph, “open” time units of 8, 4, 2, 1 would be allocated to thecontrollable valves 204 in order to have a same amount of waterdelivered to zones 1-4. Here, as noted above, the amount of time thelowest-rate controllable valve 204 is kept open is the longest in thesystem since fluid has to flow through that segment.

To put twice as much fluid in zone 2 with the same controllable valve204 configuration noted above, requires a time sequence 8, 8, 2, 1. If,however, it is desired that three times as much fluid in zone 2, it maybe necessary to decrease the emission rate of the controllable valve 204of zone 1 to 0.25 gph. Now, the sequence of controllable valves 204 willbe 0.25, 1, 2, 4 and the “open” timing would be 16, 12, 2, 1.

In accordance with embodiments, different or multiple driplines 202 canbe grouped together and controlled to thereby create “variable rateirrigation” zones. In such an approach, the “variable rate irrigation”zones can be created continuously based on information provided bymonitoring stations that would delineate the “variable rate irrigation”zones and specify the amount of fluid needed in each correspondinglocation. Such feedback information can be provided by soil moisturesensors that would monitor the water content in the soil, satellitesensing to monitor the evapo-transpiration of the associated canopy orcanopy sensors to measure local water content. Any of the sensingapproaches will have a spatial and temporal resolution determined by thedetection methods and the resolution will be matched by the length ofdrip lines segments and by updating the irrigation schedule. For commonsatellite imagery like LANDSAT, the spatial resolution will be about 15m and the temporal resolution will be 7 day.

As shown in FIG. 9B, the multiple controllable valves 204 may be coupledto the control station 14 via gateways 206. With such a configuration,the control station 14 is provided as a master unit that is responsiblefor irrigation scheduling as well as other functionalities and thecontrollable valves 204 are slave elements subject to the controlstation 14. The gateways 206 may be provided as wired or wirelesselements.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of onemore other features, integers, steps, operations, element components,and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiments were chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

While the preferred embodiments to the invention have been described, itwill be understood that those skilled in the art, both now and in thefuture, may make various improvements and enhancements which fall withinthe scope of the claims which follow. These claims should be construedto maintain the proper protection for the invention first described.

1. A controllable emitter of an irrigation apparatus including a dripline having pressurized fluid therein, the controllable emittercomprising: a container coupled to the drip line, the container beingformed to define an interior and including an inlet through which thepressurized fluid is receivable in the interior from the drip line andan outlet through which the pressurized fluid is exhaustible from theinterior; a magnetic stopper, which is normally disposable in a firstposition such that the magnetic stopper prevents a flow of thepressurized fluid through the outlet and which is actively disposable ina second position such that the magnetic stopper permits the flow; and acontrollable actuator configured to generate a magnetic field operableto urge the magnetic stopper to move from the first position to thesecond position.
 2. The controllable emitter according to claim 1,wherein the drip line is disposed substantially horizontally and thecontainer extends substantially downwardly from the drip line.
 3. Thecontrollable emitter according to claim 2, wherein the magnetic stoppersits in the outlet in the first position and has sufficient size toprevent the flow.
 4. The controllable emitter according to claim 1,wherein the container comprises a tubular element.
 5. The controllableemitter according to claim 1, wherein the magnetic stopper comprises aspherical element.
 6. The controllable emitter according to claim 1,wherein the spherical element is formed to define a bore-hole.
 7. Thecontrollable emitter according to claim 1, wherein the magnetic stoppercomprises a conical element.
 8. The controllable emitter according toclaim 1, wherein the controllable actuator comprises a solenoidsupportively coupled to the container.
 9. The controllable emitteraccording to claim 1, wherein the controllable actuator comprises aconductive element wrapped around the container.
 10. The controllableemitter according to claim 1, further comprising a controller operablycoupled to the controllable actuator, the controller being configured tocause the controllable actuator to generate the magnetic field inaccordance with a predefined condition.
 11. An irrigation systemincluding multiple drip lines and a plurality of controllable emittersdisposed along each of the multiple drip lines, each of the plurality ofcontrollable emitters being provided in accordance with the controllableemitter according to claim 1 and independently controllable. 12-20.(canceled)